Process of improving quality and increasing quantity of illuminating coal-gas.



UNITED STATES PATENT OFFICE.

FREDERICK BREDEL, OF MILWVAUKEE, WISCONSIN.

PROCESS OF IMPROVING QUALITY AND INCREASING QUANTITY OF ILLUMlNATINGCOAL-GAS.

SPECIFICATION forming part of Letters Patent No. 635,911, dated October31, 1899.

Application filed January 7, 1899. Serial No. 701,475. (No specimens.)

T0 on whom it may concern:

Be it knownthat I, FREDERICK BREDEL, a citizen of the United States,residing at Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented certain new and usefullmprovements in Processesof Improving the Quality and Increasing the Quantity To this end and tosuch others as the inventicn may pertain, the same consists in the stepshereinafter specified, which steps when taken in the order describedconstitute my improved method or process for accomplishing the objectsmentioned.

It is well known to those skilled in the art pertaining to themanufacture of illuminating coal-gas that such gas has generally beenenriched by mixing with the gas vapors of hydrocarbon. While thisprocess in a certain sense improves the quality of the gas, it is opento certain objections due to the fact that the flame produced in burninggas which has been so enriched flickers and smokes, this being due tothe fact that the hydrocarbon va pors are not fixed gases.

Another process that has been employed for increasing the candle-powerof coal-gas consists in passing the gas as soon as it leaves theretort-s through another independent and so-called -superheating retort;but this process has been found to be impractical for the followingreasons: The coal-gas contains a considerable quantity of water-vaporsas well as ammonia-vapors, which in the presence of carbon will bedecomposed while passing through a heated retort. The water-vapors aredecomposed into their elements, hy-' drogen and oxygen, which latterforms with the carbon monoxid carbonic acid, and as this latter is anon-combustible gas it serves to diminish the illuminating power of thegas in such a degreethat any possible advantages obtained by increasingthe candle-power by this process are nullified by the presence of thecarbonic acid. The ammonia present is also partially destroyed.Lampblack and retort-carbon are also formed in quantities which make theprocess undesirable. Without taking into consideration the aforesaiddisadvantages, this process is impractical from a commercial point ofview, as a very large amount of desirable by-products (ammonia and tar)is destroyed, and the process also facilitates and is directlyresponsible for the occurrence of obnoxious stoppages in the gas-mains.

The essential object of the present invention is to overcome all thesedefects and to obtain a higher candle-power.

The process consists in passing dry purified coal-gas through one ormore hot retorts. The temperature of these retorts should be from darkto bright cherry red, according to the quantity of gas passed throughthe retort. By dry purified or purified gas is meant such gas as haspassed the ordinary iron, manganese, or lime purifier. Thegenerallyaccepted theory is that by passing so-called heavyhydrocarbons, as propylene, butylene, styrol, or naphthalene, throughhot retorts the aforesaid hydrocarbons would be decomposed and that thebenzol present would also be destroyed. This might be true when thegasis passed by itself alone or if contained in unpurified gas or, inother words, in the presence of water-vapor and carbonic acid; but Ihave discovered that purified coal-gas or such gas as containspractically no watervapor or ammonia or sulfureted hydrogen whichcontains said heavyhydrocarbons acts quite differently and that the gasincreases its candle-power instead of losing it by forming otherhydrocarbons which have a higher heat of formation and therefore showahigher candle-power when burned in the so-called fiat-flame burner orthe class commonly termed the Argand burner.

The process can also be carried out by mixing the purified coal-gas withother rich hydrocarbons, such as naphtha or gasolene vapors, and passingthe same through hot retorts, whereby a further large increase inilluminating power is obtained.

The process is carried out in the following manner: Pass ten per cent.or more of purified coal-gas through one or more hot retorts and mix theso-treated reheated gas with the crude gas, preferably ahead of theexhauster. In passing the gas through the hot retorts lighterhydrocarbons are formed than those originally contained in the gas,thereby producin g a highercandle-power. These lighter hydrocarbons actagain as carriers of the heavy hydrocarbons-such as naphthalene, &c.(which latter have a very high illuminating power,)and thereby preventthe absorption of the aforesaid heavy hydrocarbon vapors by the tar, andthe resulting gas will therefore contain more illuminants than wouldotherwise be possible for it to contain or carry on account of theadmixture of said purified gas, itbeing an established fact thatcoal-gas when leaving the hydraulic main is of from twenty-four totwenty-eight candle power; but a large prop'ortion of this candlepoweris lost by cooling and washing and purifying the gas, for the reasonthat there is a lack of sufficient lighter hydrocarbons to carry theheavier. After mixing the gas obtained by passing the purified coalgasthrough the hot retorts with crude gas it is finally passed through acooling and purifying apparatus.

From the foregoing explanations the advantages possessed by my processwill be at once evident. Should it be found to be necessary to furtherincrease the candle-power of the gas, the admixture of heavy hydrocarbonvaporssuch as benzol, naphtha, or gasolene vaporsbecomes necessary. Itis advisable to mix these vapors with the gas before it enters the hotretort, and the so-treated gas is then mixed with the crude gas, asheretofore described.

The experiments that I have made show that an increase of candle-poweris obtained by passing the purified coal-gas through hot retorts andthat when mixing the so-treated reheated gas with crude coal-gas theresulting gas after purification has about the same can die-power as thereheated gas.

I am aware that the so-called blue watergas has been mixed with heavyhydrocarbon vapors and then passed through hot retorts; but this processdoes not obtain an increase of candle-power in the so-called blueWatergas itself, for the reason that the gas consists principally ofcarbon monoxid, hydrogen, and a small percentage of methan, (CH andtherefore has practically no candle-power. In my process I use coalgasor, in other words, a gas which contains a large amount of. differenthydrocarbons besides marsh-gas.

Having thus described my invention, what I claim to be new, and desireto secure by Letters Patent, is

1. The process of increasing the candlepower of coal-gas and at the sametime of increasing the quantity of gas produced per pound of coalcarbonized, the same consisting in passing the purified coal-gas throughhot retorts having a minimum temperature of a dull-red heat,substantially as and for the purpose specified.

2. The process of increasing the candlepower of coal-gas and at the sametime of increasing the quantity of gas produced per ton of coalcarbonized, which consists in passing the purified coal-gas through hotretorts having a minimum temperature of a dull-red heat, and then mixingthe gas thus obtained with crude gas, and finally passing thethus-obtained mixture through the different cooling and purifyingapparatus, substantially as described, and for the purpose specified.

In testimony whereof I aflix my signature in presence of two witnesses.

FREDERICK BREDEL.

Witnesses:

HENRY F. REILLY, GEORGE H. KATZ.

